Binary mixtures of biodegradable aliphatic polyesters and products obtained from these

ABSTRACT

A biodegradable mixture obtained by melt mixing polyesters comprising (A) an aliphatic polyester obtained from aliphatic diacids selected from the group consisting of azelaic acid, sebacic acid, brassilic acid, mixtures thereof and mixtures of said acids with aliphatic dicarbossilic acids and/or aliphatic hydroxyacids containing more than 50 mole % of azelaic acid, sebacic acid and brassilic acid, and from aliphatic diols; (B) a polymer of lactic acid in which the concentration by weight of A with respect to (A+B) is in the range of 30 to 60% and in which the sum of the fusion entalpy ΔH A  and ΔH B  of the two polyesters in the mixture is greater than the sum of the fusion entalpies ΔH 1  and ΔH 2  of the polyesters prior to melt mixing.

The present invention relates to biodegradable mixtures comprising atleast two aliphatic polyesters in proportions such that it is possibleto obtain a film, by blowing or casting, provided with improved waterbarrier properties with respect to individual polyesters, of highrigidity, transparency and biodegradability as well as solid andexpanded (foamed) sheets and associated thermoformed products withoptimum barrier properties and rigidity.

Such composite materials are particularly suitable for the foodpackaging sector.

PRIOR ART

Conventional polymers such as polystyrene, polyethylene terephthalateand similar are characterised not only by an excellent rigidity, butalso by good barrier properties against water and by good transparency.These polymers are used in the packaging sector in general, and in foodpackaging in particular, as well as in the sector of disposable dishessuch as plates, cups and cutlery. Their low biodegradability and thedifficulty of recovering the, different starting plastics in asufficiently differentiated manner upon recycling has however created anincreasing problem of disposal in recent decades.

Polymers such as L-polylactic acids, D,L-polylactic acids, D-polylacticacids and their co-polymers are biodegradable thermoplastic materialsfrom renewable sources; they are transparent with excellent resistanceto fungi and therefore suitable for packaging food as well aspreservation of their organoleptic characteristics. On the other handthey biodegrade slowly in the soil and, in compost, degrade quickly onlyat high temperatures. The greatest limitation, however, lies in the lowprocessability, upon recycling of waste, and also in that for manyapplications the permeability to water is too high.

If, on the other hand, aliphatic polyesters constituted predominantly ofmonomers from renewable sources starting from diacidic diols, inparticular polymers of sebacic, brassylic and azelaic acids areconsidered, these have the limitation that their rigidity is too low andtheir water permeability is too high. For this reason products preparedfrom these resins are also inadequate as rigid materials for packaging.

Binary mixtures of polylactic acid and aliphatic polyesters haveconstituted the subject of many patents. In particular, European PatentEP-0 980 894 A1 (Mitsui Chemical) claims a significant improvement inthe tear strength and balance of film based on a blend of polylacticacid and other polyesters such as polybutylene succinate, with a meltingpoint of between 80 and 250° C., by introducing a plasticiser into theblend. This, however, gives a non-transparent film with, in any event,very modest strength of the order of 120 g in accordance with the JISP8116 method. The presence of a plasticiser, moreover, placeslimitations on contact with food, and the disadvantage of ageingphenomena.

U.S. Pat. No. 5,883,199 relates to binary mixtures of polylactic acidand polyester with the polyester forming a continuous or co-continuousphase and the polylactic acid content lying between 10 and 90%. Suchmixtures, in accordance with the indicated examples, do not showsignificant reduction in the permeability to water or steam.

EP-1 033 383 relates to a biodegradable film comprising a polylacticacid-family polymer and other aliphatic polyester than the polylacticacid-family polymer charactherized in that the heat for fusion convertedto the polylactic acid-family polymer when the temperature of the filmis raised is 35 J/g or under. Such patent does not deal with the problemof improving the barrier properties against water of the biodegradablefilm and one of the main target of the invention is to find out abiodegradable film with excellent heat sealability. Among the otheralyphatic polyester used toghether with the polylactic acid-familypolymer, EP-1 033 383 describes as preferable polyesters havingdicarboxilic acid units and aliphatic diol units among whichpolybutylene sebacate is mentioned even though mixtures of said polymerwith a polylactic acid family polymer do not show at all heatsealability properties such as those claimed in the patent. On thecontratry the heat sealability properties are very poor and even lowerthan those reported in the comparative examples not belonging to theinvention.

SUBJECT OF THE INVENTION

Starting from the problem of finding a material able to combineproperties of transparency, rigidity and water barrier it has nowsurprisingly been found that by combining a polymer of polylactic acidwith diacid/diol aliphatic polyesters in specific ratios as describedhereinafter there is a critical range of compositions in which it ispossible to obtain, entirely unexpectedly, a significantly lowerpermeability to water with respect to the individual polymers, as wellas modulus of elasticity in tension greater than any envisaged from theHalpin/Tsai mixture rule, and an optimum transparency.

DESCRIPTION OF THE INVENTION

The invention relates to a biodegradable mixture obtained by melt mixingpolyesters comprising:

-   -   (A) An aliphatic polyester obtained from aliphatic diacids        chosen among azelaic acid, sebacic acid and brassilic acid, or        mixtures thereof with aliphatic dicarbossilic acids and        hydroxyacids containing more than 50 mole % of azelaic acid        and/or sebacic acid and/or brassilic acid, and from aliphatic        diols said polyester having a modulus of elasticity comprised        from 400 and 900 MPa and a breaking elongation greater than 200%        on blown film of about 25-30 μm, average ponderal molecular        weight greater than 55,000 and a melting point from 40 to 95°        C.;    -   (B) A polymer of lactic acid comprising L or D polylactic acid,        L,D-polylactic, meso polylactic acid and lactic acid copolymers        with hydroxyacids or lactones thereof containing at least 75% of        L-lactic or D-lactic acid with average ponderal molecular weight        higher than 70,000 and with a modulus of elasticity greater than        1500 MPa;    -   in which the concentration by weight of A with respect to (A+B)        is in the range from 30 to 60% and blown films of thicknesses of        25-30 μm have a modulus of elasticity greater than 1400 MPa, a        permeability to water comprised from 170 to 40 g30 μM/m²24 h and        in which the sum of the fusion entalpies ΔH_(A) and ΔH_(B) of        the two polyesters A) and B) in the mixture is greater than the        normalized sum of the fusion entalpies ΔH₁ and ΔH₂ of the        aliphatic polyesters A) and B) prior melt mixing.

For normalised sum it is meant the sum obtained by multiplying the ΔH₁and ΔH₂ fusion entalpies for the percentage divided by 100 of the twopolyesters present in the mixture.

The increase of the fusion entalpies ΔH_(A)+ΔH_(B) of the two polyestersin the mixture with respect to their normalised sum ΔH₁+ΔH₂ shows anunexpected increase of cristallinity in the mixture which is the causeof the surprisingly very low value of the permeability to water and thelow heat sealability exibited by the composition according to theinvention.

The mixture of biodegradable polyesters according to the invention isobtained from a process which involves working in a twin screw or singlescrew extruder in temperature conditions between 140 and 200° C.,performing the two steps of the mixing process and film forming togetheror separately. Film forming separate from the mixing process is achievedwith conventional machines for the extrusion of low or high densitypolyethylene with a temperature profile in the range between 140 and200° C., and it is possible to obtain films having thicknesses lyingbetween 5 and 250 μm. Film forming at temperatures lying between 185 and200° C. is preferred.

Film with thicknesses of 25-30 μm has characteristics of transparencylying in the range 35-80% for the source transmittance, and in theinterval 90-95% for the entry point transmittance. The permeability tosteam or water at 38° C. with a relative humidity on one side of thefilm of 10%, to obtain a Δ relative humidity of 90% in staticconditions, lies between 170 and 40 grams of water referred to 30 μm ofthickness of the film which passes through a square metre of surface intwenty-four hours (g30 μm/m²24 h) and more preferable between 120 and 70grams (g30 μm/m²24 h). The individual polymers constituting the mixtureaccording to the invention, in the same film conditions, give values ofpermeability lying between 200 and 800 gr. (g30 μM/m²24 h).

The tensile properties in the longitudinal film direction in terms ofmodulus of elasticity measured according to ASTM 882 exceed 1000 MPa andpreferably 1400 MPa.

In the mixing phase polymers of type A with MFI (150° C., 2.16 kg) lyingbetween 1 and 10 dg/min are preferred and polymers C with MFI (i90° C.,2.16 kg) lying between 2 and 30 dg/min are preferred.

The polymer (A) includes, as above specified, polyesters obtained fromazelaic, sebacic or brassilic acids or mixtures thereof in mixture withless than 50% by moles of aliphatic dicarbossilic acids and/or aliphatichydroxyacids.

Typical hydroxy acids include glycolic acid, lactic acid,3-hydroxybutyric, 4-hydroxybutyric, 3-hydroxyvaleric, 4-hydroxyvaleric,and 6-hydroxycaproic acid and further includes cyclic esters ofhydroxycarboxylic acids such as glycolides, dimers of glycolic acid,ε-caprolactone and 6-hydroxycaproic acids. Mixtures of these acids canbe used.

Examples of aliphatic dicarbossilic acids are oxalic acid, malonic acid,succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid,undecandioic acid, and dodecandioic acid.

Specific glycols useable in the preparation of the A) polyester areethylene glycol, diethylene glycol, triethylene glycol, polyethyleneglycol, 1,2- and 1,3-propylene glycol, 1,3-butandiol, 1,4-butandiol,3-methyl -1,5-pentandiol, 1,6-hexandiol, 1,9-nonondiol, dipropyleneglycol, 1,11-undecandiol, 1,13-tridecandiol, neopentyl glycol,polytetramethylene glycol, 1,4-cyclohexane dimethanol and cyclohexanediol. Mixtures of these glycols can be used.

All the compounds above mentioned are combined in such a way as to formpolyesters with mechanical characteristics of tensile resistance toelongation greater than 300% and modulus of elasticity lying between 400and 900 MPa on blown films of at least 30 μm thickness and with amelting point between 40 and 95° C., preferably between 55 and 85° C.and more preferably between 57 and 79° C. Particularly preferredpolyesters are those preferably containing more than 70 mole % and evenmore preferably more than 90 mole %, of the total of units deriving fromazelaic, sebacic, or brassylic acid or their mixtures.

Also included in polymers of type A are polyamide polyesters where thepolyester part is as described above and the polyamide part can becaprolactam, and aliphatic diamine such as hexamethylene diamine or evenan amino acid. The type A polyesters can also contain aromatic diacidsin quantities less than 5 moles %. Polycarbonates also belong topolymers of type A.

The polyesters can beobtained by polycondensation or, as in the case ofglycolides and lactones, by ring opening according to known methods.Morever, polyesters can be branched polymers with the introduction ofpolyfunctional monomers such as glycerine, epoxyoized soya oil,trimethylpropane and the like or polycarboxylic acids such asbutantetracarboxylic acid.

Regrading with isocyanates can take place in the molten state at the endof the polymerisation reaction or in the extrusion phase, or in thesolid state as described in the Novamont Patent WO 99/28367. The twotypes of polymers A and B can also have additives such as chainextenders or cross linking agents of the type described above in themixing phase.

Ratios between polymer A and polymer B different from those indicatedfor the mixtures according to the present invention give rise toproducts not having sufficient barrier properties and, in the case ofexcessively high content of polymer A, excessively low modulus ofelasticity.

The material obtained from the mixture of two polymers A and B does notneed plasticisers which create problems of migration especially for foodpackaging. However, quantities of plasticisers below 5% with respect topolymers A+B can be added.

Various additives can also be incorporated in the mixture, such asantioxidants, UV stabilisers, stabilisers against heat and hydrolysis,flame retardants, slow release agents, organic and inorganic fillerssuch as, for example, natural fibres, anti-static agents, humectants,colorants and lubricants.

In particular, in the production of blown or cast film the following canbe added: silica, calcium carbonate, talc, kaolin, kaolinite, zincoxide, wollastonites, various hydrotalcites and in general lamellarinorganic substances whether or not functionalised with organicmolecules capable of delamellating in the mixing phase with thepolymeric mixture or with one of the individual polymers of the mixtureto give nanocomposites with improved antiblocking and barrierproperties. The various inorganic substances can be used in mixtures orwith individual products. The concentration of the inorganic additivesis generally between 0.05 and 30%, preferably between 0.5 and 20%.

To improve the film-forming characteristics there can be added amides ofaliphatic acids such as oleamide, stearamide, erucamide, behenamide,N-oleylpalmitamide, N-stearylerucamide and other amides, salts of fattyacids such as aluminium, zinc or calcium stearate and the like. Thequantities of these additives vary from 0.05 to 7 parts and preferablybetween 0.1 and 5 parts of the polymer mixture.

The mixture thus obtained can be transformed into a film by blowing orextrusion through a flat head, can be extruded as a solid sheet or afoamed or expanded sheet and then heat formed. The films aretransparent, have a high resistance to water (water barrier) withrespect to the biodegradable starting materials according to CEN 13432,and moreover have a sufficient rigidity for food packagings whichrequire rigid films. The film is poorly weldable and can be obtained inthickness up to 5μm by blowing or casting.

In the non-food field the films obtained with the mixture according tothe invention are excellent for applications such as films for adhesivetape, tapes for nappies, for ornamental coloured tapes, for adhesivetapes of different form and use and moreover in applications such asbags for clothing, or film for wrapping flowers, plants and giftobjects.

In the food field the films obtained from the mixture according to theinvention, thanks to their very low value of permeability, are excellentfor applications such as packets for dried products (biscuits, crackers,crisps, chipsters and the like), chocolate, cheese, meat, vegetablesetc. In addition, the low heat-sealability of the mixture according tothe invention allows specific applications in the food field such asjoining and tear strip films for sealing food containers.

The films advantageously find use also in agriculture or in any eventfor outside use and can contain UV stabilisers in the form of individualfilms or coextrusions with films having a low modulus, as in the case ofstarch-based materials, to give improved UV resistance, improved barrierproperties, and a different rate of degradation in the atmosphere and inthe ground.

The films can moreover be surface treated with aluminium or silica orothers, and can be laminated with other materials so as to combinedifferent characteristics (barrier to oxygen and/or to water,peelability, connectability etc). For these cases, as particularlyadvantageous examples of practical applications, one can mentioncontainers for yoghurt, cheese, meat, bread, biscuits, potatoes andsnacks in general, bowls for industrial use, and containers for fragileobjects such as eggs.

The films can advantageously be used as the component of a multi-layerfilm composed of at least one layer of polylactic acid or otherpolyester, non-destructured starch (and its blends with synthetic andnatural polymers) or as components of a multi-layer with aluminium andother materials or with a vacuum metalised layer with aluminium, silicaand other inorganic materials. The multi-layers can be obtained bycoextrusion or by lamination or by extrusion coating, if one layer ispaper or other material which does not melt between 100 and 200° C.

The biodegradable polymer compositions according to the invention canmoreover find advantageous use in the form of articles different fromfilm. For example, they can be used to obtain fibres for textiles andnon-woven textiles, or for fishing nets. Moreover, the non-woven fabriccan be used in the sanitary sector for nappies, sanitary towels etc. Thefibres can also be utilised as weldable reinforcing fibres in specialpapers.

The compositions can also be utilised with success also for theproduction of sheets for thermoforming, extruded or coextruded withother layers of polymers such as polylactic acid or other polyesters orpolyamides or materials based on starch then thermoformed to formcontainers for food, agriculture and others. The material can be usedfor injection moulding of containers, cutlery or other things, and has avery high speed of crystallisation and a very high crystallinity.

The material according to the invention can also contain polymericadditives such as polyethylene waxes and polypropylene, PET and PTB,polystyrene, copolymers of ethylene and propylene with functionalcarboxylic groups, carboxylate, methacrylate, acrylate or hydroxylicgroups or else combined with these polymers in coextrusions,coinjections or the like. The material can be utilised as a matrix inthe blend with destructured starch according to the processes describedin Novamont Patents (EP-0 327 505, EP-0 539 541, EP-0 400 532, EP-0 413798, EP-0 965 615 with the possibility of forming complexes with thestarch or simply utilising the destructured starch, converted and/orcomplexed as a submicronic filler for the polyester.

They can be used as coating films for biodegradable expanded materialsbased on polyesters, polyamides; thermoplastic starch and complexedstarch or simply blends of starch with other polymers or with thematerial of the present invention.

The material, as it is or in mixture with starch or other polymers canbe obtained as an expanded material to form containers for fruit andvegetables, meat, cheese and other food products, or containers for fastfood. It can also be obtained in the form of expanded particles whichcan be agglomerated for industrial packaging or in the form of injectedfoam.

The mixture according to the invention will now be described with thefollowing non-limititive examples.

EXAMPLES Examples 1-7

Polymers constituting the mixture:

-   -   Aliphatic polyester: polybutylene sebacate produced from sebacic        acid and butandiol with monobutyl stannoic acid catalyst        according to Example 1 of WO 00/55236.    -   Poly L-lactic acid with a D-lactic content of 6%: 4040 Cargill.

Formed into a film on a Ghioldi machine:

-   -   Diameter=40mm, L/D=30; rpm=45; die: diameter=100 mm; air gap=0.9        mm; land=12; flowrate=17 kg/h; temperature profile:        120-150-190×2; temperature filter=190×2; head temperature=190×2.    -   Film: width=400 mm; thickness=25 μm.

The determination of the values of transmittance, both at the sourceport (T_(SOURCE)) and at the entry port (T_(entr)) was effected by meansof a HAZEGUARD SYSTEM XL-211.

The values of breaking load (α), elongation at break (ε) and modulus ofelasticity (E) were determined in accordance with the ASTM D 882-91 bymeans of an INSTRON 4502 instrument.

The values of permeability, expressed in g30 μm/m²24 h were determinedat 38° C. with a relative humidity of 10% on one side of the film toguarantee a Δ humidity equal to 90% in static conditions with cups ofdiameter 61.8 mm and a depth of 28.5 mm filled with H₂O to a height of10 mm from the bottom. The cups were put in a climatic cell positionedwithin a perforated box which guarantees the absence of air currentswithin it which may cause possible turbulence phenomena on the surfaceof the specimen, and thus an uncontrolled increase in the exchangeefficiency. The values found identify the grams of water referred to 30μm of thickness of film which passed through a square metre of surfacein twenty-four hours.

Results of the tests conducted are plotted in Table 1. Tests 1-6 wereeffected on mixtures containing 0.3% of erucamide (slip agent) whilstTests 1a, 3a, 5a, 6a and 7 were conducted on mixtures without erucamide.

The heat-seal strenght of the mixture according to example 3 was testedaccording to the method disclosed in EP-1 033 393; values lower than 0.5Kg/15 mm were obtained

Comparative Examples 8-11

Comparative examples 8-11 were made with BIONOLLE a commerciallyavailable aliphatic polyester: examples 8-9 with BIONOLLE 1903(polybutylensuccinate homopolymer) and example 10-11 with Bionolle 3001(polybutylensuccinate-adipate copolymer). The films obtained accordingto these examples show permeability values outside the range of thecompositions according to the present invention.

Table 2 shows the ΔH values referred to the polyesters component of themixture prior to melt mixing (ΔH₁ and AH₂) and to the polyesters in themixture (ΔH_(A) and ΔH_(B)). The table refers to the compositions ofexample 3, 5, 9 and 11. Examples 3 and 5 are according to the inventionwhereas examples 9 and 11 refer respectively to Bionolle 1903 andBionolle 3001.

The values have been determined on films of about 25-30 μm. A PerkinElmer DSC 7 analyzer was used. ΔH₁ and ΔH₂ are the fusion entalpy valuesof the polyesters prior to melt mixing. ΔH₁+ΔH₂ is the sum of the heatfusion values normalized in relation to the mixtures percentages. Thevalues are expressed in J/g. The Differential Scanning Calorimetry hasbeen performed raising the temperature at a rate of 20° C. per minute.

TABLE 1 A/ Permeability σ ε Ε Example A % B % A + B g30 μm/m² 24 hT_(source) % T_(entr) % (MPa) (%) (MPa)  1 100 0 100 544 71 94 46 646629  1a 100 0 100 714 — — — — —  2 60 40 60 170 38.5 90.4 36.5 362 1464 3 50 50 50 86 67 92.8 35 60 2007  3a 50 50 50 82 — — — — —  4 40 60 4069 73 92 34 69 2018  5 30 70 30 84 79.7 92.4 38 202 2166  5a 30 70 30107 — — — — —  6 0 100 0 274 92 95 58 6 2517  6a 0 100 0 292 — — — — — 7 70 30 70 442 — — — — —  8 100 0 100 635 70.5 94.0 64 355 790  9 50 5050 180 82 94.0 47 281 1580 10 100 0 100 1013 73 94.0 62 505 332 11 50 5050 269 83 94.0 43 386 1327

TABLE 2 Polylactic Polylactic Polyester:Polylactic Polyester acidPolyester acid Example acid ΔH1 ΔH2 ΔH1 + ΔH2 ΔHA ΔHB ΔHA + ΔHB 3 50:5088 29.9 58.95 64 15.8 79.8 5 30:70 88 29.9 47.3 39.4 12.8 52.2 9 50:5059 29.9 44.5 13.99 22.57 36.56 11 50:50 38 29.9 33.95 11.8 14.9 26.7

1. A biodegradable mixture obtained by melt mixing polyesterscomprising: (A) An aliphatic polyester obtained from aliphatic diacidsselected from the group consisting of azelaic acid, sebacic acid,brassylic acid, mixtures thereof and mixtures of said acids withaliphatic dicarboxylic acids and/or aliphatic hydroxyacids containingmore than 50 mole % of azelaic acid, sebacic acid and brassylic acid,and from aliphatic diols said polyester having modulus of elasticitylying between 400 and 900 MPa and breaking elongation greater than 200%on blown film of about 25-30 μm, average ponderal molecular weightgreater than 55,000 and a melting point from 40 to 95° C.; (B) A polymerof lactic acid chosen among L or D polylactic acid, L,D-polylactic, mesopolylactic or lactic acid copolymer with hydroxyacids or lactonesthereof containing at least 75% of L-lactic or D-lactic acid havingaverage ponderal molecular weight greater than 70,000 and with modulusof elasticity greater than 1500 MPa; in which the mixture containsplasticizers in quantities less than 5% by weight with respect to thequantity of aliphatic polyester and polymer of the lactic acid theconcentration by weight of A with respect to (A+B) is in the range of 30to 60% and blown films of thickness between 25-30 μm have modulus ofelasticity greater than 1400 MPa, permeability to water from 170 to 40g30 μm/m²24 h a transmittance at the entrance port lying between 90 and95% and in which the sum of the fusion enthalpy ΔH_(A) and ΔH_(B) of thetwo polyesters in the mixture is greater than the sum of the fusionenthalpies ΔH₁ and ΔH₂ of the polyesters prior to melt mixing.
 2. Amixture according to, claim 1 in which the aliphatic polyester isobtained from mixtures of azelaic acid and/or sebacic acid and/orbrassylic acid with aliphatic dicarboxylic acids and, optionally,aliphatic hydroxyacids containing more than 70 mole % of azelaic acidand/or sebacic acid and/or brassylic acid.
 3. A mixture according toclaim 2, in which the hydroxy acid is selected from the group containingglycolic acid, lactic acid, 3-hydroxybutyric, 4-hydroxybutric,3-hydroxyvaleric, 4-hydroxyvaleric, 6-hydroxycaproic, and cyclic estersof hydroxycarboxylic acids, glycolidies, dimmers of glycolic acid,ε-caprolactone and 6-hydroxycaproic acid.
 4. A mixture according toclaim 1 in which the aliphatic diol is selected from the groupcomprising ethylene glycol, diethylene glycol, triethylene glycol,polyethylene glycol, diethylene glycol, 1-2 and 1-3 propylene glycol,1,3-butandiol, 1,4-butandiol, 3-methyl-1,5-pentandiol, 1,6-hexandiol,1-9 nonandiol, dipropylene glycol, 1, 11-undecandiol, 1,13-tridecandiol,neopentyl glycol, polytetramethylene glycol and 1,4-cyclohexanedimethanol, cyclohexane diol or mixtures thereof.
 5. A film produced byblowing or flat head extrusion from mixtures according to claim
 1. 6. Afilm according to claim 5, in which the mixture contains one or moreinorganic additives such as silica, calcium carbonate, talc, kaolin,kaolinite, oxide of zinc, wollastonite, hydrotalcite, lamellar inorganicsubstances functionalized or not with organic molecules capable ofdelamellating in the mixing phase with the polymeric mixture or with oneof the individual polymers of the mixture to give nanocomposites.
 7. Afilm according to claim 6 in which the content by weight of inorganicadditives in the mixture lies between 0.05 and 3.0.
 8. Packets for foodor industrial products and clothing, adhesive tapes, tapes for napples,coloured ornamental tapes, adhesive tapes of different form, film forpackaging flowers, plants and gift items, produced from film accordingto claim
 7. 9. Bags and films for dry products such as bread, biscuits,crackers, crisps, chipsters, chocolate, cheese, meat, vegetables,welding and tear tape, and film for sealing containers, produced fromfilm according to claim
 7. 10. Film according to claim 7 surface treatedwith aluminum or silica or laminated.
 11. Multi-layer film comprising atleast one film according to claim 7 and one layer of polylactic acid orother polyester or destructured or non-destructured starch and itsblends with synthetic and natural polymers said multi-layer filmoptionally comprising a layer of aluminium and other materials or avaccum-metalized layer with aluminum, silica and other inorganicmaterials.
 12. Fibers for woven and non-woven textiles or for fishingnets produced from mixtures according to claim
 1. 13. Sheets forthermoforming, extruded or coextruded with other layers of polymers thenthermoformed into trays for food, and agricultural products obtainedfrom mixtures according to claim
 1. 14. Containers for yoghurt, cheese,meat, biscuits, crisps, snacks, trays for industrial use, containers forfragile objects, produced from sheet according to claim
 13. 15.Containers, cutlery, disposable objects, injection moulded frombiodegradable polymeric mixtures according claim
 1. 16. Foam sheetproduced with mixtures according to claim 1 and formed into containersfor food such as meat, cheese, vegetables, drinks, containers for fastfood.
 17. Agglomerable expanded particles produced from biodegradablepolymeric mixtures according to claim 1 for packages for use in theindustrial sector.